In the past 2,3,6-trimethylphenol has been manufactured from the reaction of m-cresol with methanol utilizing various catalyst systems such as described in DAS 1,263,010, Mar. 14, 1968; DAS 1,269,125, May 5, 1968; Japanese Patent Publication 37,942/72, Sept. 25, 1972; and DAS 2,124,901, Dec. 16, 1971. Such known processes for the manufacture of 2,3,6-trimethylphenol in which catalyst systems of various types are used, generally have the disadvantage that the yields of the desired products are relatively small. Furthermore, the catalysts used generally have a relatively short life.